Portuguese health number

Hello

I wanted to know how to register myself and children to get our ‘numero de utente de saude.’ We are British nationals with the Brexit withdrawal residency document. Is it a fairly straightforward process? We will be going to the ‘centro de saude’ in Amora (Lisbon) but the website was confusing for us. What are the steps we need to take and how long will it take to get our ‘numero de utente de saude?’ Is it instant and on the spot like the NIF? What documents will they want to see? We have to take time out on a weekday to do this so as much information and direction as possible would be much appreciated.

I can’t seem to find useful information about this anywhere. Is the residency document for Brexit enough for this?

Thanks

Just curious to know if you tried to use EHIC/GHIC? Was it not working for you?